JP2007239847A - Pipe connecting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple and inexpensive pipe connecting structure capable of obtaining high sealability. <P>SOLUTION: The pipe connecting structure is for fastening and fixing the outer periphery of an end of an outer pipe 2 with an end of an inner pipe 1 inserted therein with a C-shaped clamp 4. On the outer pipe 2, a second enlarged-diameter portion 22 having a larger diameter than a first enlarged-diameter portion 21 is formed on the pipe end via the first enlarged-diameter portion 21 into which the pipe end of the inner pipe 1 is inserted. An annular gasket 3 is interposed between a base portion of the second enlarged-diameter portion 22 and the inner pipe 1. A plurality of slits 22a are formed on the pipe end of the second enlarged-diameter portion 22 in the axial direction to a position where one portion is over the annular gasket 3. Locking pieces 22c are bent and formed so that tip ends of separated pieces 22b separated by the slits 22a protrude outward. The separated pieces 22b separated by the plurality of slits 22a on the second enlarged-diameter portion 22 are fastened by the C-shaped clamp 4 to reduce the diameter of the outer pipe 2 to the outer diameter of the inner pipe 1 and fastening the pipes. Thereby, the annular gasket 3 is pressurized in the base portion direction of the second enlarged-diameter portion 22, to be pressed against a tapered step portion 23, and the outer peripheral face of the inner pipe 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pipe connection structure such as an exhaust pipe.

  Conventionally, the following is known as a pipe connection structure.

  Conventional Example 1 .. As shown in FIG. 5 (half-sectional view) and FIG. 6 (viewed in the direction of arrow A in FIG. 5), the inner pipe 102 is formed in the pipe end of the outer pipe 101 having a slit 101a formed at the end. The tube end portion of the outer pipe 101 is inserted and the overlapping portion of the inner pipe 102 and the slit 101a portion of the outer pipe 101 is tightened with a C-type clamp 103 (see, for example, Patent Document 1).

  Conventional Example 2 .. As shown in FIG. 7 (half-sectional view) and FIG. 8 (viewed in the direction of arrow B in FIG. 7), flanges 203 and 203 are provided near the end of the inner pipe 201 and the end of the outer pipe 202. A structure in which both flanges 203 and 203 are fastened with bolts 205 via a gasket 204 in a state where the pipe end of the inner pipe 201 is inserted into the pipe end of the outer pipe 202 (see, for example, Patent Document 2).

Conventional Example 3 .. As shown in FIG. 9 (half-sectional view) and FIG. 10 (viewed in the direction of arrow C in FIG. 9), the outer periphery of the inner pipe 301 is inserted into the end of the outer pipe 302. The inner pipe 301 is formed with a chevron-shaped bead 301a bulging radially outward near the end thereof, and the outer pipe 302 is A flare 302a is formed at the end thereof so as to expand radially outward and abut on the end side tapered surface of the chevron-shaped bead 301a, and the C-type clamp 303 includes a fastening bolt and a nut 304 between the two fastening flanges. The inner pipe 301 is inserted into the outer pipe 302 and the flare 302a is brought into contact with the end-side tapered surface of the bead 301a, and then tightened with a C-shaped clamp 303 from the outside. Structure for connecting the pipe 301 and the outer pipe 302 (e.g., see Patent Document 3.).
Utility Model Registration No. 2594341 JP-A-9-68037 JP 2002-235880 A

  However, the conventional pipe connection structure has the following problems.

  The pipe connection structure of Conventional Example 1 is simple in structure as described above, but has a problem that there are many gas leaks, and it has hardly been adopted recently.

  In the pipe connection structure of the conventional example 2, there is a problem that the use of the flanges 203 and 203 as described above is expensive and heavy.

  In the pipe connection structure of Conventional Example 3, as described above, it is necessary to form the chevron-shaped bead 301a that bulges radially outward near the end of the inner pipe 301. The chevron bead 301a is formed. In order to achieve this, the pipe expansion rate of the inner pipe 301 far exceeds 30%. In particular, when the wall thickness of the inner pipe 301 is thin due to the demand for weight reduction, the normal pipe expansion method causes cracks and many defective products. As a result, a special construction method is required, which results in a time-consuming process using special equipment, resulting in a cost increase.

  The problem to be solved by the present invention is to provide a pipe connection structure that has a simple structure, is inexpensive, and provides high sealing performance.

  In order to solve the above problem, the pipe connection structure according to claim 1 is a pipe connection structure in which the outer periphery is clamped and fixed by a fastening fixing means in a state where the end of the inner pipe is inserted into the end of the outer pipe. The outer pipe has a tapered stepped portion having a second diameter-expanded portion having a diameter larger than that of the first diameter-expanded portion through a first diameter-expanded portion into which the tube end of the inner pipe is inserted. An annular gasket is interposed between the base of the second enlarged diameter portion and the inner pipe, and a pipe end portion of the second enlarged diameter portion reaches a position partially related to the annular gasket. A plurality of slits are formed in the axial direction, a locking piece is bent so that the tip of the separation piece separated by the slit protrudes outward, and the plurality of slits in the second enlarged diameter portion The separated piece is tightened with the fastening and fixing means to the outer diameter of the inner pipe. The annular gasket is configured to be pressed against the tapered stepped portion and the outer peripheral surface of the inner pipe by pressing the annular gasket toward the base portion of the second enlarged diameter portion by reducing the diameter. As a means.

  In the pipe connection structure of the present invention, as described above, the outer pipe has a second diameter larger than that of the first enlarged diameter portion via the first enlarged diameter portion in which the pipe end of the inner pipe is inserted into the pipe end portion. An enlarged diameter portion is formed, and an annular gasket is interposed between the base portion of the second enlarged diameter portion and the inner pipe, and a pipe end of the second enlarged diameter portion is pivoted to a position related to the annular gasket. A plurality of slits are formed in the direction, and the locking piece is bent so that the tip of the separation piece separated by the slit protrudes outward, and is separated by the plurality of slits in the second enlarged diameter portion By tightening the separation piece with the fastening and fixing means and reducing the diameter to the outer diameter of the inner pipe, the annular gasket is pressed toward the base of the second enlarged diameter portion, and the tapered step portion and the outer peripheral surface of the inner pipe By being configured to press against the ring, it is annular between the base of the second enlarged diameter portion and the inner pipe Basket since become a state of being strongly clamped radially, the effect is obtained that it is possible to ensure a cheaper high sealing properties with a simple structure.

  Embodiments of the present invention will be described below with reference to the drawings.

  The pipe connection structure of the first embodiment corresponds to the invention described in claim 1.

  First, the pipe connection structure of the first embodiment will be described with reference to the drawings.

  1 (a) to 1 (c) are half sectional views showing the connection process of the pipe connection structure of the first embodiment, and FIGS. 2 (a) to (c) are D and E in FIGS. 1 (a) to (c). FIG.

  This pipe connection structure includes an inner pipe 1, an outer pipe 2, an annular gasket 3, and a C-type clamp (fastening and fixing means) 4.

  More specifically, the main body portion of the inner pipe 1 and the outer pipe 2 is formed to have substantially the same outer diameter as shown in FIGS. 1 (a) and 2 (a). A second enlarged-diameter portion 22 having a larger diameter than the first enlarged-diameter portion 21 is formed via a first enlarged-diameter portion 21 into which the pipe end of the inner pipe 1 is inserted at the end of the tube. A tapered step portion 23 is formed between the first and second enlarged diameter portions 22.

  The outer pipe 2 has the annular gasket 3 interposed between the base of the second enlarged diameter portion 22 and the inner pipe 1, and the annular gasket 3 is connected to the pipe end of the second enlarged diameter portion 22. A plurality of slits 22a are formed in the axial direction up to the position related to the part.

  The locking piece 22c is bent so that the tip of the separation piece 22b separated by the slit 22a protrudes outward.

  The C-type clamp 4 serves to tighten and tighten the separation piece 22b separated by the plurality of slits 22a in the second diameter-expanded portion 22 to the outer diameter of the inner pipe 1, and has a notch arc shape. Fastening flange portions 42, 42 project substantially parallel to both ends of the main body portion 41, and the fastening flange portions 42, 42 are tightened with bolts and nuts 43 so that the notched arc-shaped main body portion 41 is reduced in diameter and fastened. It has become.

  Next, operations and effects of the first embodiment will be described.

  Since the pipe connection structure of the first embodiment is configured as described above, first, as shown in FIG. 1A, the annular gasket 3 is mounted on the inner base portion of the second enlarged diameter portion 22 of the outer pipe 2. Then, the pipe end portion of the inner pipe 1 is inserted into the annular gasket 3 and the first enlarged diameter portion 21 of the outer pipe 2, and as shown in FIG. 1 (b), a plurality of slits 22a in the second enlarged diameter portion 22 are used. By tightening the separated piece 22b with the C-shaped clamp 4 and reducing the diameter to the outer diameter of the inner pipe 1 and fastening it, a force to move the annular gasket 3 in the direction of the base of the second enlarged diameter portion 22 acts. As shown in (c), the annular gasket 3 is strongly sandwiched in the radial direction between the tapered step portion 23 at the base of the second enlarged diameter portion 22 and the inner pipe 1.

  Therefore, according to the pipe connection structure of the first embodiment, it is possible to obtain an effect that a simple structure is inexpensive and high sealing performance can be secured.

  Next, another embodiment will be described. In the description of the other embodiments, the same components as those of the first embodiment are not shown, or the same reference numerals are given and the description thereof is omitted, and only the differences are described.

  The second embodiment shows a modification of the pipe connection structure in the first embodiment and corresponds to the invention described in claim 2.

  That is, the pipe connection structure of the second embodiment has a portion fastened with a C-type clamp 4 in the inner pipe 1 as shown in FIG. 3 (half-sectional view) and FIG. The difference from the first embodiment is that an outward annular bead 11 that is lower than the inner peripheral surface of the second enlarged diameter portion 22 of the outer pipe 2 is provided between the annular gasket 3 and the interposed portion. is there.

  In the second embodiment, as described above, the outer annular bead 11 that is lower than the inner peripheral surface of the second diameter-expanded portion 22 is protruded, so that the diameter of the outer pipe 2 is reduced by tightening the C-type clamp 4. Further, the pipe end fastening portion of the second enlarged diameter portion 22 is axially locked to the outward annular bead 11, and the movement of the inner pipe 1 in the pipe end direction is prevented, so that the pipe can be prevented from coming off. It becomes like this.

  Further, when the tube end portion of the second enlarged diameter portion 22 in the outer pipe 2 is fastened by the C-type clamp 4, the end edge portion of the C-type clamp 4 is locked to the locking claw 22c, and therefore the outwardly annular shape A force that draws the entire outer pipe 2 toward the pipe end acts along the inclined surface of the bead 11, whereby the tapered step portion 23 between the first diameter-expanded portion 21 and the second diameter-expanded portion 22 and the outside The annular gasket 3 is also sandwiched between the directional annular beads 11 in the axial direction, and an additional effect is obtained in that the sealing performance can be further improved.

  Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment, and design changes and the like within a scope not departing from the gist of the present invention are included in the present invention.

  For example, in the embodiment, the C-type clamp 4 is used as the fastening and fixing means, but other known fastening and fixing means can be used.

6 is a half cross-sectional view showing a connection process of the pipe connection structure of Example 1. FIG. It is a D, E, F arrow line view of FIG. It is. It is a half sectional view showing a connection process of the pipe connection structure of Example 2. FIG. 4 is a G arrow view of FIG. 3. It is. It is a half sectional view showing the pipe connection structure of Conventional Example 1. It is A arrow directional view of FIG. It is. It is a half sectional view showing the pipe connection structure of Conventional Example 2. It is a B arrow line view of FIG. It is. It is a half sectional view showing the pipe connection structure of Conventional Example 3. It is C arrow line view of FIG. It is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner pipe 11 Outward annular bead 2 Outer pipe 21 1st enlarged diameter part 22 2nd enlarged diameter part 22a Slit 22b Separation piece 22c Locking piece 23 Tapered step part 3 Annular gasket 4 C type clamp (fastening fixing means)
41 Notched arc-shaped body part 42 Fastening flange part 43 Bolt / Nut

Claims (2)

A pipe connection structure in which the outer periphery of the inner pipe is inserted into the end of the outer pipe and the outer periphery thereof is fastened and fixed by a fastening fixing means,
The outer pipe has a second enlarged portion having a diameter larger than the first enlarged portion through a tapered step portion through a first enlarged portion into which the pipe end of the inner pipe is inserted into the pipe end portion. Formed,
An annular gasket is interposed between the base of the second enlarged diameter portion and the inner pipe,
A plurality of slits are formed in the axial direction up to a position related to the annular gasket at the pipe end portion of the second enlarged diameter portion,
The locking piece is bent so that the tip of the separation piece separated by the slit protrudes outward,
The annular gasket is connected to the second enlarged portion by tightening the separation piece separated by the plurality of slits in the second enlarged portion by the fastening and fixing means and reducing the diameter to the outer diameter of the inner pipe. The pipe connection structure is configured to press against the tapered step and the outer peripheral surface of the inner pipe.   2. The pipe connection structure according to claim 1, wherein an outer portion lower than an inner peripheral surface of a second enlarged-diameter portion of the outer pipe is interposed between a portion of the inner pipe fastened by the fastening fixing means and the annular gasket interposed portion. A pipe connection structure characterized in that a direction-oriented annular bead is protruded.

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